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- Reading of the input time series required for the Hydstra model run (e.g. precipitation, temperatur, discharge) as provided through from the general adapter through the FEWS Published Interface XML format (PI-XML), and transforming these to the input format required by the Hydsra model engine (Hysdstra Time Series Format, TSF).
- Amending the Hydstra model definition file (TSO file) with the appropriate run-time parameters (e.g. model start time, run length etc). These data are provided from the FEWS General Adapter through the PI-XML formatted run file.
- Amending the value of model parameters and states within the TSO file to allow influencing the behaviour of the Hydstra model. These parameters can be set either using the PI-XML parameters file exported from the FEWS General adapter (typically used for setting the value of model parameters, or through an PI-XML time series (typically used for setting the value of a model state at the start of the run).
- Reading the output time series provided by the Hydstra model engine. These outputs are provided by the model engine using two formats; TSF formatted files and free format text files (format specified in the TSO file).
Hydstra model definition file
Each of the basin models that can be run through the Hydstra adapter is defined in the Hydstra Model Definition File (Model TSO file). This defines all model inputs and outputs, model structure and model parameters. While the Hydstra adapter does not interpret the full file, there are specific sections that are important. The model structure is made up of a series of nodes and links,, where each node is a modelling element of a defined type (this refers to a specific modelling algorithm such as the Synthetic Streamflow and Reservoir Routing - SSARR, or Unit Hydrograph - UH, algorithms). Links are important in this context to identify the inputs to the model as external time series are connected to the algorithms defined in the nodes though these links.
When setting up the Hydstra model to run from FEWS, it is important to identify all expected input time series. These are identified through the key word Source=TimeSeries. An example is provided below:
Source=TimeSeries(59.233,28.893,Text(C:\fews_systems\FEWS-Alberta\FEWS_ARFS\FEWS_ARFS\Modules\hydstra\Work\05DB006_QR.tsf),Agg)